Extremely heavy loads such as machinery, equipment, presses, and the like, are subjected to shock and vibration and are susceptible to misalignment due to these forces and/or due to settling including settling of the building floor or building foundation. (As used herein and in the appended claims, the term “machinery” is used generically, and is intended to include all such machinery, equipment, apparatus, etc.) Proper alignment, including leveling, flatness, and the like, is essential in order to operate efficiently, economically and safely. Therefore it is important to diminish or substantially eliminate shock and vibrations.
The prior art discloses various types or designs of adjustable mounts or isolating mounts to correct for out-of-level or out-of-flatness conditions. In addition, it is desirable to protect or isolate the machinery from the surrounding environment as much as possible from the damaging effects of shock and vibration generated by the machinery. Heavy machinery, for example punch presses standing twenty feet or higher and weighing as much as a million pounds or more, can be damaged or become misaligned. Therefore it is necessary to absorb or dampen as much of the shock and vibration as possible. Isolators utilized for this purpose, as known or shown in the art, incorporate, in general, a damping means interposed between the load and a bearing member positioned on a substructure, and include friction isolating dampers, hydraulic isolating dampers, and viscous isolating dampers. In the prior art, the isolating machinery mount typically incorporates an elastomeric cushion member, which is positioned below a bearing member and rests on the substructure or building floor. In this manner, the machine is protected from undersirable shock and vibrations.
This prior art includes, for example, U.S. Pat. Nos. 3,332,647; 4,047,427; 4,648,577; and 4,846,436. In U.S. Pat. No. 4,648,577, a damper plunger of a frusto-conical configuration includes a top plate for supporting the load (i.e., the machinery) and is positioned for movement in and out of a housing containing a viscous damping medium. The frustum plunger has holes in the wall for throttling the viscous medium upon movement of the viscous medium, and preferably includes a bank of tubes to provide an additional damping force.